Saw blade construction

ABSTRACT

A saw blade construction and method of forming such blade whereby the ends of a saw blade are abutted into end to end relationship to define an endless saw blade having a series of teeth formed along one edge to define a cutting edge, and having a back edge which is progressively sloped or tapered in opposite directions from an intermediate point on the back edge so that in a cutting operation the saw blade effects a cut along an edge portion of a workpiece on the down feed stroke of the blade and a progressive cut on the opposite edge of the workpiece whereby the teeth are rendered self-feeding on the progressive cut of the workpiece. In a modified embodiment the saw blade is formed with a plurality of alternately disposed down feed and progressive cutting edges. 
     The respective saw blades when so formed have a tapered rear edge which has one or more step cams spaced along the rear length thereof, which results in an improved cutting action and sawing speed; particularly, for materials such as hard metals, like stainless steel, Inconal and the like.

RELATED APPLICATIONS

This application is a continuation-in-part application of my applicationSer. No. 842,618 filed Oct. 17, 1977 and now U.S. Pat. No. 4,160,397,for Saw Blade Construction and Method of Making Same.

PROBLEM AND PRIOR ART

Heretofore, saw blades, e.g., endless band or saw blades were formedwith cutting teeth generally disposed parallel to the back edge of theblade, and which teeth effected a cut by scratching rather than byeffecting a progressive cut. Such blades required a considerable amountof cutting pressure to be applied to the blade. Such pressure wasdetrimental to the blade as it frequently caused the blade to be twistedand/or distorted. Such twisting or distortion during a cutting operationalso adversely affected the accuracy of the cut.

In an effort to overcome these apparent deficiencies, I have caused tobe patented a method of producing a stepped saw blade as disclosed in myU.S. Pat. No. 4,023,448 granted May 17, 1977. While the saw bladeconstruction in accordance with the methhod of said U.S. Pat. No.4,023,448 constitutes a substantial advance in the art, the presentinvention to be herein described constitutes a further advance in theart of saw blade constructions and method of forming same.

OBJECTS

An object of this invention resides in the provision of a saw bladeconstruction and method of forming such blade in which the respectiveteeth over a portion of a cutting edge during a cutting operation areprogressively fed relative to a workpiece during a cutting operation,and whereby another portion of the cutting edge effects a cuttingoperation on the down feed stroke of the blade.

Another object is to provide an improved saw blade construction andmethod of making same which is relatively simple, inexpensive, andpositive in operation.

Another object is to provide an endless band saw construction whereinthe back edge of the blade is tapered or progessively sloped outwardlyrelative to the cutting edge in opposite direction from an intermediatepoint.

Another object is to provide an endless saw blade construction having aplurality of connected segments having sloped or tapered back edgeextending in opposite direction from a series of spaced apartintermediate points.

Another object is to provide an endless saw blade construction having anoppositely tapered back portion whereby the cutting edge is slopedduring a cutting operation to effect a cut on the down feed side of thesaw blade and a progressive cut on the cutting stroke of the blade.

SUMMARY OF THE INVENTION

The foregoing objects and other features and advantages are obtained bya saw blade construction which comprises a saw blade having a series ofcutting teeth disposed along an edge thereof to define a cutting edge.The opposed ends of a blade of a predetermined length are disposed inend to end relationship and secured to define an endless blade. The backof the blade is shaped so as to taper outwardly in opposite directionfrom an intermediate point. The arrangement is such that during acutting operation, a portion of the blade effects a cut on a workpieceduring the down feed stroke of the blade, and another portion of theblade effects a progressive cut whereby the cutting teeth areprogressively fed during the cutting operation. Thus the bladeconstruction is such at a see-saw type cutting action is effected on theworkpiece which will greatly enhance the cutting operation.

The method for fabricating a saw blade embodying the present inventioncomprises of forming a series of cutting teeth along a predeterminedlength of a blade stock. Thereafter, the back edge of the blade is cutor shaped with oppositely disposed tapers extending from an intermediatepoint on the back edge of the blade. The opposed ends of the blade arethen joined to define an endless band blade having a minimum width and aspaced apart maximum width, whereby the back edge of the blade is slopedrelative to the cutting edge. An alternate method is to join the ends ofthe predetermined length of the saw blade together and thereafter shapeor cut the back edge to slope the back edge relative to the cuttingedge. Still another method can comprise tapering the back edge of theblade from one end to the other, then joining the opposed ends wherebythe back edge is stepped, and thereafter, cut, grind or remove thestepped portion of the back edge to finish the blade construction.

FEATURES

A feature of this invention resides in an improved method of fabricatingan endless saw blade which is capable of greatly enhancing the cuttingoperation and the accuracy of the cutting operation.

Another feature resides in an improved saw blade construction of theendless band type where the blade effects a progressive cut on theworkpiece on one side thereof, and a down feed cut on the other side ofthe workpiece to result in a continuous see-saw type cutting action onthe workpiece.

Another feature resides in an endless band saw blade constructionwherein the cutting action is effected with a continuous see-saw typecutting action in which the cutting teeth are progressively presented tothe workpiece on the non feed cycle of the cutting stroke.

Other features and advantages will become more readily apparent whenconsidered in view of the drawings and specification in which:

FIG. 1 is a side view of a saw blade stock.

FIG. 2 is a side view of a saw blade showing an intermediate step.

FIG. 3 is a perspective view of an endless saw blade embodying thepresent invention.

FIGS. 4, 5, and 6 are respective views corresponding to views 1, 2 and 3respectively of a modified blade construction.

FIGS. 7, 7A, 8 and 9 are respective views illustrating the steps andconstruction of a modified saw construction.

FIGS. 10, 11 and 12 are views corresponding to views 1, 2, and 3respectively of still another modified blade construction.

FIG. 13 is a diagrammatic view to illustrate the see-saw cutting actionon a workpiece of an endless blade embodying the present invention.

FIG. 14 is a perspective view of a modified embodiment.

FIG. 15 is a detail expanded side view of the blade length of FIG. 13.

FIG. 16 is a perspective view of another modified embodiment of a bandsaw having a plurality of step cams formed along the rear edge thereof.

FIG. 17 is a detail expanded side view of the blade length of FIG. 15.

Detailed Specification

Referring to the drawings, there is shown in FIG. 3 an improved endlessband or saw blade 20 embodying the present invention. The saw blade 20is defined by an elongated member or saw blade stock 21. As best seen inFIG. 1, the saw blade stock 21 has a series of cutting teeth 22 formedalong one edge to define the cutting edge. It will be understood thatthe teeth 22 formed along the cutting edge or constructed according towell known technology. The edge opposite the cutting edge defines a backor rear edge 23 which is generally parallel to the cutting teeth edge.It will be also understood that the blade length L may be of anypredetermined length.

According to this invention, the back edge 23 of the blade is shaped bycutting or grinding along the dash lines 23A as shown in FIG. 1 todefine a blade configuration as indicated in FIG. 2.

The back edge of the blade 21 after being shaped defines oppositelydisposed inclined or tapered edge portions 23B and 23C which extendoutwardly from an intermediate point 24 on the back edge 23. In the formof the invention shown in FIGS. 1 to 3, the intermediate point 24 islocated midway between the opposed end portions 25--25 of blade 21.Referring to FIG. 2, it will be noted that the back edge portions 23B,23C taper outwardly and incline relative to its corresponding cuttingedge portions 23B¹ and 23C¹. Thus the transverse width W of the blade atthe intermediate point defines the minimal width or transverse sectionof the blade 21. The opposed end portion 25 defines the maximumtransverse width W¹.

With blade stock 21 so formed, the endless blade 20, as shown in FIG. 3,is formed by bringing the opposed end portions 25--25 together andjoined as by welding or other suitable bonding technique as indicated at26. Upon completion of the endless band saw blade 20 as shown in FIG. 3,it will be noted that proceeding clockwise as indicated by arrow 27, thecross sectional width of the blade progressively increases in going fromW or point 24 to W¹ or joint 26. From joint 26 or W¹ to point 24 or Wthe cross section width of the blade 20 progressively diminishes.

With the construction described and the method defined for the assemblyof blade 20, it has been discovered that in a cutting operation blade 20will effect a see-saw type cutting action on a workpiece 28. Referringto FIG. 13, the endless band 20 is disposed in a sawing machine, notshown, so that the blade 20 is fed vertically toward the workpiece 28.At the cutting station on opposite sides of the workpiece, the back edgeof the blade is disposed in engagement with a pair of spaced pressurerollers 29 and 30. One roller, e.g., roller 29, functions as the bladedown feed roller, and which roller exerts a pressure on the blade 20during the down feed cutting stroke. Thus on the down stroke, thepressure of rollers 29 and 30 is such that the cutting is being effectedto the left of the centerline CL of the workpiece, the cutting edgeportion 23B¹ effects a progressive cutting action on the workpiece 28 tothe right of the centerline CL as viewed in FIG. 13.

The arrangement is such that the pressure rollers 29 and 30 applies aforce on the blade which tends to render the tapered back edge of theblade 20 coincidental thus disposing the cutting edge portions 23B¹ and23C¹ at an angle relative to the back edge. It will be understood thatthe degree of taper formed along the back edge as shown in FIGS. 1 and 2will vary in accordance to a desired cutting operation or material to becut. p With the blade construction described and the manner in which itfunctions, it will be noted that on the feed stroke, edge portion 23C¹is effecting a cutting action on one side of the workpiece whereby theteeth are not progressively fed during this portion of the cuttingoperation, and thereafter, the cutting stroke is effected or followed byblade portion 23B¹ whereby the cutting teeth are progressively renderedself-feeding over this portion of the cut. Thus, the arrangement is suchthat the cut is effected by a back and forth or see-saw type of cuttingaction on the workpiece 28.

FIGS. 4, 5 and 6 illustrate a modified blade construction and method offorming an endless blade of the type embodying this invention. In thisform of the invention, the blade construction 30 and method of formingthe same is similar to that hereinbefore described, except that theminimal width or point 24¹ is located at a point other than the midpointof blade 31. Thus as shown in FIGS. 4 and 5, the length of taper formedalong the back edge 32 of blade 31 are of unequal length, e.g., 32A and32B whereby 32A is longer than 32B; the latter defining a step cam. Whenthe opposed ends 33--33 are joined as at 34, the arrangement is suchthat the down feed of the cutting stroke is effected over the distancedefined by the short taper or step cam 32B, and the progressive cut iseffected over the longer edge 32A. In all other respects the operationof the blade construction of FIG. 6 is similar to that hereinbeforedescribed. Also the manner in which blade 31 operates is similar asdescribed with respect to FIG. 13, except that the down feed of theblade 31 is effected over the length of the short taper 32B, and theprogressive cut is effected over the length of the longer taper orleading edge 32A.

FIGS. 7, 7A, 8 and 9 illustrate the various constructional steps toillustrate another method of making an endless band saw 40 embodying theinvention. In this form of the invention, a blade stock 41 is formedwith a series of cutting teeth 42 to define a cutting edge along thelength thereof. The back edge 43 is cut or shaped along a cutting line43A on blade 40 so as to define a longitudinal taper back edge 43extending from end to end 44--44.

As shown in FIG. 8, the opposed ends 44, 44 are then joined to oneanother in a suitable manner to define and endless blade 40. The ends44--44 are joined so that the teeth define a circular or coincidentalbottom cutting edge. With the endless blade formed as shown in FIG. 8,the back edge portion 45 is removed along a cutting line or plane 46 inan outwardly or progessively tapered manner to an intermediate point,e.g., 47. Upon effecting the removal of the portion 45 along cutline 46as described, an endless blade construction as shown in FIG. 9 isproduced. In the finished form, the abutted end portions 44 define theminimal transverse section of the blade, and the transverse section atpoint 47 defines the maximal transverse section. Thus, a blade 40 havingopposed outwardly tapered back edge portions 46A, 46B from point 44 isformed. The blade 40 formed by the method described is structurallysimilar to that described with respect to FIGS. 1 to 3. However, asdescribed in FIGS. 4, 5, and 6, the intermediate point 47 of blade 40may be located at any desired intermediate point along the length of theblade so as to vary the length of the respective down feed cut andprogressive cut as hereinbefore described.

FIGS. 10, 11 and 12 illustrate a further embodiment and method forforming such embodiment. As best seen in FIG. 12 the endless band saw 50has a plurality of opposed tapered or sloping back edge portions, e.g.,51A, 51B, to define more than one minimal transverse section 52--52, andmaximal transverse sections 53, 53.

Referring to FIG. 10, the saw blade stock member 54 is formed withcutting teeth 54A in a well known manner. The back portion 55 is thencut or shaped along a cutting line 56 to define a back edge 57 as shownin FIG. 11. Thus the stock member 54 is formed with alternate minimaland maximum transverse sections as indicated at 52 and 53. The opposedends 53 are then joined to define the endless band saw blade as shown inFIG. 12.

The band saw blade of FIG. 12 is thus constructed to define a multipledown feed cutting portion and a multiple progressive cutting portion pereach revolution of the blade 50. In operation, the blade 50 of FIG. 12operates in a manner hereinbefore described with respect to FIG. 13,except that upon each revolution of blade 50, a multiple down feed cutand progressive cut is made.

From the foregoing, it will be apparent that the improved band saw bladeand method of forming the same results in a saw blade which can effect aquick and efficient cut with a minimum of power and with a maximum ofaccuracy. It will be noted that each blade construction, as described,operates with a down feed cut occuring to one side of a workpiece andwith an alternate progressive cut on the other side of the workpiece. Inso doing, the cutting operation is rendered more efficient than theconventionally known cutting methods. Also by locating the minimaltransverse section relative to an end portion of a blade member, as bestseen in FIGS. 2 and 4, the length of the progressive cut can be varieddepending upon the material to be worked upon.

FIGS. 14 and 15 illustrate a modified embodiment. In this form of theinvention, the saw blade 60 comprises a blade segment 61 of apredetermined length having cutting teeth 62 formed along one edge ofthe blade. It will be understood that the cutting teeth are formed in aconventional and well known manner. The back or rear edge 63 of the sawblade segment is tapered or inclined from one end to the other so thatthe respective end portions 61A and 61B have different transversewidths, wherein the respective transverse width sections of the bladeprogressively increase from end 61A to 61B.

The blade segment 61 is formed into an endless blade as seen in FIG. 14by bringing the ends 61A and 61B into abutting relationship and securingthe ends by any suitable means such as welding, brazing or by a suitablebonding technique. The ends 61A and 61B are joined so that the teeth orcutting edge lie in a common plane. Thus, when the ends are so joined, acam step 64 is defined at the juncture of the end portions, as best seenin FIG. 14. The structure of blade 60 is such that the back or rear edgeof the blade is tapered over the segmental blade length between ends 61Aand 61B.

The band saw 60 formed as shown in FIG. 14 is used in a band saw machineso that the guides or pressure rollers act on the rear or back edge 63of the saw blade 60 causes the blade to be abruptly moved as the highpoint of the step cam 64 passes the pressure rollers, and as the bladecontinues to advance it is gradually moved relative to the workpiece soas to effect a progressive cut.

While FIGS. 14 and 15 illustrate a saw blade having one step cam 64formed on the rear thereof, it will be understood that the blade may beformed with a plurality of step cams 64' as seen in a modified form ofFIG. 16. In the embodiment of FIG. 16, it will be noted that the blade70 can include two or more blade segments 71 and 71A of a desiredpredetermined length. In all other respects blade 70 of FIG. 15 issimilar to that described with respect to FIGS. 14 and 15.

FIG. 17 shows the blade 70 of FIG. 16 in its expanded linear form.

The blade construction embodied in FIGS. 15 to 16 can be readily formedby forming the saw blade 60 or 70 from conventional stock blade materialand forming the cutting teeth along one edge in accordance withconventional technology. Such blades may be continuously formed andthereafter the respective desired blade length being severed from thecontinuously formed blade.

According to this invention, the rear or back edge of the blade oppositethe cutting teeth is shaped by cutting, grinding or the like to defineone or more step cams 64 or 64' at spaced intervals therealong. When therear edge is so formed, the opposed ends of the blade of a given lengthare joined so that the teeth along the endless cutting edge lies in aflat plane. Thus a step cam is formed along the back edge whereby theback edge is sloped or tapered relative to the cutting edge. It will beunderstood that the step cam and tapered rear edge may be shaped beforejoining the ends of a given blade length or after the ends have beenjoined.

It will be noted that while the step cam 64 or 64' of FIGS. 14 and 16define a substantially vertical or normal drop relative to thelongitudinal axis of the blade, the step cam can be angled or sloped asshown in FIG. 6 as indicated at 32B.

As shown in FIG. 6, the step cam indicated by slope 32B, while theleading edge 32A slopes more gradually whereby the width of the blademeasured transversely from the cutting edge to the rear edge varies froma low point 24' to a high point 34; the difference between low point 24'and high point 34 being the height of the cam step. In all otherrespects the blade of FIG. 6 is similar to that described with respectto FIGS. 14 to 17.

The teeth of the respective described and illustrated blades are similarin size or shape and are formed in a well known manner.

While the foregoing invention has been described with respect to severalsaw blade embodiments and methods of forming the same, it will beunderstood and appreciated that variations and modifications can be madewithout departing from the spirit or scope of the invention.

I claim:
 1. A saw blade comprising a blade stock having a rear edge anda cutting edge, said cutting edge having a series of cutting teethwhereby said cutting teeth lie in a common plane, said rear edge beingprogressively inclined relative to said common plane of said teeth, andsaid blade stock having a minimum and maximum transverse section, andsaid minimum and maximum transverse sections being contiguously disposedto define a cam step along the back edge of said blade.
 2. A saw bladeas defined in claim 1 wherein said blade stock includes a plurality ofconnected blade segments, each blade segment having a minimum traversesection at one end thereof and a maximum transverse section at the otherend of said blade segment, the minimum transverse end section of onesegment being disposed contiguous to the maximum traverse end section ofa next adjacent segment so as to define a plurality of said cam stepsspaced along the back edge of said blade.
 3. A saw blade as defined inclaim 1 wherein the ends of said blade stock are joined to define anendless band saw.
 4. A band saw blade as defined in claim 1 wherein saidcam step is disposed normal to the longitudinal axis of the blade.
 5. Aband saw blade as defined in claim 1 in which said step cam has aleading portion and a trailing portion, and said leading portion slopesgradually upwardly from the low point of said cam to the high point ofsaid cam.